After World War I, the British Government agreed to set up two self-governing regions in Ireland: Northern Ireland (made up of four Ulster counties with Protestant/unionist majorities and two others), and Southern Ireland. However, by 1920 the Irish War of Independence was raging and the Irish Republican Army (IRA), the army of the self-declared Irish Republic, was launching attacks on British forces in Ireland. As a response to these attacks, the UVF was revived. However, this revival was largely unsuccessful and the UVF was absorbed into the Ulster Special Constabulary (USC), the reserve police force of the Northern Ireland Government.

On 13 January 1913, the Ulster Volunteer Force (UVF) was formally established by the Ulster Unionist Council.[4] Recruitment was to be limited to 100,000 men aged from 17 to 65 who had signed the Covenant, under the command of Lieutenant-General Sir George Richardson KCB.[5]William GIbson was the first commander of the 3rd East Belfast Regiment of the Ulster Volunteers.[6]

The Ulster Unionists enjoyed the wholehearted support of the British Conservative Party, even when threatening rebellion against the British government. On 23 September 1913, the 500 delegates of the Ulster Unionist Council met to discuss the practicalities of setting up a provisional government for Ulster, should Home Rule be implemented.[7]

In March 1914, the British Army's Commander-in-Chief in Ireland was ordered to move troops into Ulster to protect arms depots from the UVF. However, 57 of the 70 officers at the Army's headquarters in Ireland chose to resign rather than enforce Home Rule or take on the UVF. The following month, the UVF smuggled 20,000 German rifles with 3,000,000 rounds of ammunition into the port of Larne. This became known as the Larne gunrunning.

The Ulster Volunteers were a continuation of what has been described as the "Protestant volunteering tradition, in Ireland", which since 1666 spans the various Irish Protestant militias founded to defend Ireland from foreign threat.[9] References to the most prominent of these militias, the Irish Volunteers, was frequently made, and there were also attempts to link the activities of the two.[9]

Although many UVF officers left to join the British Army during the war, the unionist leadership wanted to preserve the UVF as a viable force, aware that the issue of Home Rule and partition would be revisited when the war ended. There were also fears of a German naval raid on Ulster and so much of the UVF was recast as a home defence force.[14]

World War I ended in November 1918. On 1 May 1919, the UVF was 'demobilised' when Richardson stood down as its General Officer Commanding. In Richardson's last orders to the UVF, he stated:

Existing conditions call for the demobilisation of the Ulster Volunteers. The Force was organised, to protect the interests of the Province of Ulster, at a time when trouble threatened. The success of the organisation speaks for itself, as a page of history, in the records of Ulster that will never fade.[15]

As a response to IRA attacks within Ulster, the Ulster Unionist Council officially revived the UVF on 25 June 1920.[16] In early July, the UUC appointed lieutenant colonelWilfrid Spender as the UVF's Officer Commanding.[16] At the same time, announcements were printed in unionist newspapers calling on all former UVF members to report for duty.[16] However, this call met with limited success; for example, each Belfast battalion drew little more than 100 men each and they were left mostly unarmed.[16] The UVF's revival also met with little backing from unionists in Great Britain.[16]

During the conflict, loyalists set up small independent "vigilance groups" in many parts of Ulster. Most of these groups would patrol their areas and report anything untoward to the police (the RIC). Some of them, however, were armed with UVF rifles from 1914.[17] There were also a number of small loyalist paramilitaries. The most notable of these was the Ulster Imperial Guards, who may have overreached the UVF in terms of membership.[17] Historian Peter Hart wrote the following of these groups:

Also occasionally targeted [by the IRA] were Ulster Protestants who saw the republican guerrilla campaign as an invasion of their territory, where they formed the majority. Loyalist activists responded by forming vigilante groups, which soon acquired official status as part of the Ulster Special Constabulary. These men spearheaded the wave of anti-Catholic violence that began in July 1920 and continued for two years. This onslaught was part of an Ulster Unionist counter-revolution, whose gunmen operated almost exclusively as ethnic cleansers and avengers.[18]

The sluggish recruitment to the UVF and its failure to stop IRA activities in Ulster prompted James Craig to call for the formation of a new special constabulary.[19] In October 1920, the Ulster Special Constabulary (USC) was set up. This was an armed reserve police force whose main role, during 1920–1922, was to bolster the RIC and fight the IRA. Spender encouraged UVF members to join it, and although many did so, the USC did not engulf the UVF (and other loyalist paramilitaries) until early 1922.[19] Craig hoped to "neutralise" the loyalist paramilitaries by enrolling them in the C Division of the USC; a move that was backed by the British government.[20] Historian Michael Hopkinson wrote that the USC, "amounted to an officially approved UVF".[21] The USC was almost wholly Protestant and was greatly mistrusted by Irish Catholics and Irish nationalists. Following IRA attacks, its members sometimes carried-out revenge killings and reprisals against Catholic civilians during the conflict.[22]

In his book Carson's Army: the Ulster Volunteer Force 1910–22, Timothy Bowman gave the following as his last thought on the UVF during this period:

It is questionable the extent to which the UVF did actually reform in 1920. Possibly the UVF proper amounted to little more than 3,000 men in this period and it is noticeable that the UVF never had a formal disbandment ... possibly so that attention would not be drawn to the extent to which the formation of 1920–22 was such a pale shadow of that of 1913–14.[23]